Ramin Beyranvand1, Rahim Mirnasouri2, Saeid Mollahoseini1, Sadegh Mostofi2
1Faculty of Physical Education and Sport Science, Shahid Bahonar University of Kerman, Kerman, Iran
2Department of Physical Education and Sport Science, Lorestan University, Khorramabad, Iran
Original article Abstract
We aimed to assess and compare functional stability of the upper limbs in healthy and rounded shoulder gymnasts. A total of 30 male gymnasts aged 9-12 were selected according to the study inclusion and exclusion criteria and were assigned into a healthy and a rounded-shoulder group. The Upper Quarter Y-balance test was used to assess the functional stability of the upper limbs on the dominant and non-dominant sides. The paired t-test was used to compare the dominant and non-dominant arms and the independent t-test to compare the results between the two groups. The results obtained showed no significant differences in the functional stability of the upper limbs between the dominant and non-dominant sides.
Furthermore, the functional stability of the upper limbs was found to be significantly higher in the healthy group compared to the rounded-shoulder group. It can be concluded that having rounded shoulders can significantly affect the YBT-UQ scores obtained and increase the risk of future injuries by reducing the functional stability of the upper limbs in closed kinetic chains. Rounded-shoulders should therefore be further addressed and efforts should be made to correct this problem in gymnasts so as to reduce their risk of developing upper limb injuries.
Keywords: Functional stability, upper limb, rounded shoulders, gymnastics.
INTRODUCTION
The popularity of gymnastics has significantly increased among people in recent years and has led to a substantial increase in the number of people active this field, which may be due to the emphasis on women’s exercise, the great talents in this field, the outstanding
performances of some athletes and the inherent attractiveness of gymnastics(Sands, 2000). Following the increase in its popularity in different countries, the age of entry into gymnastics has decreased dramatically; for elite gymnasts to achieve sufficient
Science of Gymnastics Journal 280 Science of Gymnastics Journal years is the increasing complexity and the wide range of skills developed in this field, which in turn have led to changes in its movements. For instance, changes in the design of equipment, such as spring flooring, has caused changes in a variety of movements, and the increase in the number of rotations and spins and the increasing range of movement have made the field more difficult and increased the risks associated with these skills (Caine &
Maffulli, 2005). Given the increasing popularity of gymnastics and the lower age of entry into the field and the start of training before the growth period, and also given the greater difficulty and complexity of gymnastics skills in recent years, concerns about the degree and severity of injuries in this field are well justified(Caine et al., 2008). Attention to upper limb injuries is particularly important in gymnastics, because, unlike in other fields, the upper limbs are extensively used for weight-bearing and dynamic closed chain exercises in gymnastics, which makes this part of the body the second most common part for gymnastics injuries(Webb and Rettig, 2008). According to studies, upper limb gymnasts suggest that injured gymnasts are larger in physical size (i.e. height and weight) and also have a greater body fat percentage compared to healthy and less-injured gymnasts (Lindner & Caine, 1993;
Steele & White, 1986). The growth spurt age also contributes significantly to the
risk of injury (Caine & Lindner, 1985;
Micheli, 1983); in one study, Difiori et al.
(2002) reported that 10 to 14 year-old gymnasts are significantly more likely to develop upper limb injuries compared to those outside this age range (DiFiori et al., 2002). A previous history of injury also contributes significantly to the risk of injury in elite gymnasts. About 30% of all injuries occurred in gymnastics have the deviation from the normal state of the body can adversely affect people’s performance and movement efficacy by changing the direction of the transfer of force and thus expose them to physical injuries by making them change the movement strategies they use (Desai et al., 2007).
Rounded shoulders comprise one of the most common musculoskeletal abnormalities that affect normal postural alignment in the upper limbs, making it deviate from its standard position (Peterson et al., 1997). This abnormality has been described as the protraction and elevation of the scapula and the forward positioning of the shoulders that makes the chest appear caved (Kendall et al., 1983;
Kendall et al., 1970; Oyama, 2006).
Researchers differentiate between rounded shoulders as an abnormality and kyphosis or excessive curvature of the spine;
Kendall et al. (1970) showed that rounded shoulders occur on the horizontal plane while kyphosis occurs on the vertical plane (Kendall et al., 1970). Moreover, in rounded shoulders, the scapula are distanced, potentially resulting in winged scapula or the internal rotation of the humerus bones. Rounded shoulders cause changes in the static position of the scapula on the horizontal plane and may also cause the retraction of this muscle and
Science of Gymnastics Journal 281 Science of Gymnastics Journal subsequently the lengthening or
attenuation of the rhomboid muscles by approximating pectoralis minor muscle heads to the coracoid process and 3rd, 4th and 5th ribs (Kluemper et al., 2006; Lynch et al., 2010). A reduction in the relaxation length of the pectoralis minor muscle can increase passive tension in this muscle when moving the arms, thereby limiting normal upward rotation, posterior slide and the outward rotation of the scapula (Borstad, 2006). Considering the changes that can occur in the pectoral girdle function due to rounded shoulders, this condition needs to be further addressed, especially among gymnasts compared to the general public, since the upper limbs are extensively used in gymnastics for weight bearing and closed kinetic chain activities, and thus any deformity in the pectoral girdle may increase the likelihood of injury in gymnasts by changing the physical function of the upper limbs (Webb and Rettig, 2008).
Of the tests designed to assess the performance of the upper limbs, very few evaluate the performance and dynamic stability of this region in closed kinetic dynamic performance of the upper limbs in a closed kinetic chain in conditions where stability is required during movement (similar to the conditions presenting in gymnastics) with minimum equipment (Gorman et al., 2012; Westrick et al., 2012). This test quantitatively assesses the functional stability of the subject when bearing his weight on only one hand in a three-point plank position and reaching maximum distance from the supporting hand in the medial, lower-side and upper-side directions (Butler et al., 2014). This test involves simultaneous central and shoulder stability and requires balance, neuromuscular control, proprioception, power and an extensive range of
movement and is considered an efficient method for learning about performance, power and motor deficit in the shoulder (Butler et al., 2014; Gorman et al., 2012;
Westrick et al., 2012). It thus appears that using this functional test can adequately predict the likelihood of injury in closed chain activities. Given the lack of studies on the effect of postural abnormalities on upper limb performance and the functional stability of the shoulders in closed chain activities, the present study was conducted to answer the question of whether or not rounded shoulders can affect the motor performance of the upper limbs in gymnasts in closed chain movements.
METHODS
The present causal comparative study was conducted to assess and compare the functional stability of the shoulder joint in a healthy group of gymnasts and another group with rounded shoulders. The study population consisted of 60 male gymnasts aged 9 to 12 who had regularly played gymnastics three days per week for the last three years. Participants' health status was determined prior to entering the study according to the General Health Questionnaire and written consents were obtained from them after they were briefed on the study objectives and methods.
Ethical approval for this study has been granted by the Ethics Committee of the Lorestan University of Medical Sciences.
Based on previous studies (Zandi et al., 2016), a total of 30 gymnasts were selected and placed in a healthy group (n=15) and a group with rounded shoulders (n=15).
Participants with a history of head, spinal cord or upper limb fracture or surgery, those with 25<BMI<20 and those with a history of general joint hyperlaxity, neck osteoarthritis or pain in the neck and back were excluded from the study (Zandi et al., 2016).
The initial screening of the participants was performed using the New York physical examination with a chart
Science of Gymnastics Journal 282 Science of Gymnastics Journal screen (McRoberts et al., 2013) and 15
subjects with normal shoulders were randomly placed in the healthy group and 15 subjects with rounded shoulders were also randomly placed in the rounded-shoulder group.
The participants with rounded shoulders were quantified using a method consisting of percutaneous marking, digital photography (using Sony Cybershot DSC-WX200 camera) and AutoCAD 2014 (Aali et al., 2013; Raine & Twomey, 1994). In one study, Raine et al. (1994) reported a high validity and reliability for this method in the assessment of rounded shoulders (ICC=0.91)(Raine & Twomey, 1994). For this assessment, all the participants were first asked to remove their upper clothing and stand in front of the examiner. The seventh cervical vertebrae and the left and right acromion processes were marked as reference points, and in order to assume a normal position, the participants were asked to perform the military "at ease march" a number of times, rotate their shoulders forward and backward three times and then move their head backward and forward a few times (Najafi &
Behpoor, 2012). Once the normal position was assumed, the examiner photographed the positioning of their head and shoulders in the sagittal view. This step was repeated three times, and in each repeat, participants’ normal position was photographed, and the mean of the three angles obtained was ultimately recorded for each participant as the angle at which their shoulders were rounded. The photographs taken were uploaded into a computer and their different angles were assessed using AutoCAD. For this purpose, the angle between the horizontal line and the line passing through the seventh vertebrae and acromion process (Figure 1) was calculated and taken as the shoulder protrusion in degree(Aali et al., 2013; Raine and Twomey, 1994). All the measurements were taken at the same time (5-8 pm) by the same examiner.
Figure 1. The photographic assessment of rounded shoulders.
The YBT-UQ was performed using special tools designed for the test, including a plane surface on which to place the supporting hand, and bars pointing at three directions in order to determine the reach in each direction. A movable cursor was placed on each bar to be slid by the free hand in order for the extension of reach in that particular direction to be measured (Zandi et al., 2016). To perform this test, the participant was asked to position the palm of his supporting hand so that the thumb and index finger were touching and the elbow was extended outward. In this stance, the toes had to be positioned as shown in Figure 2, and the spinal cord and lower limbs had to remain aligned. The position of the thumb was marked by a line and the feet were shoulder width apart. In this position, the participant was asked to reach as far as he could in the medial, lower-side and upper-side directions using his free hand while maintaining the position of his trunk, supporting hand and lower limbs (Figure 2).
Science of Gymnastics Journal 283 Science of Gymnastics Journal Figure 2. Reach in the medial (A),
lower-side (B) and upper-lower-side (C) directions.
The action of reaching was performed consecutively in all three directions without rest and without the free hand touching the ground, and after each round (i.e. a reach in all three directions), the participant removed his stationary hand from the plane surface or touched or leaned on the ground or cursor with his free hand and also if he was unable to return to the starting position with his free hand and lost his balance, or if one of his feet was lifted from the ground (Gorman et al., 2012). The participants were allowed distance between the seventh cervical vertebrae spinous process and the end of the longest finger at a 90-degree angle between the shoulder and the extended elbow, wrist and fingers). The highest extension of reach in each direction was eventually recorded (to the nearest 0.5 cm) and the overall combined score was calculated using the following equation (Cook, 2010; Zandi et al., 2016).
Combined score = (Medial reach + lower-side reach + upper-side reach)/(length of the upper limbs×3)
To compare the reach scores in the different directions, the scores were taken separately with the length of the upper limbs and the normalized reach score in each direction.
The collected data, including participants' details and the study variables, were analyzed in SPSS-20 using descriptive and inferential statistics. The Shapiro-Wilk test confirmed the normal distribution of the variables. The paired t-test was used to compare the results obtained about participants' dominant and non-dominant limbs, and the independent t-test was used to compare the results between the healthy group and the group with rounded shoulders (P≤0.05). The examiner first performed a pilot run of the tests on four subjects and then proceeded to performing the tests on the study participants once they had resolved all the problems.
RESULTS
Table 1 presents participants' demographic details by group. The independent t-test was used to determine the homogeneity of the groups in terms of the noted indices; however, no significant differences were observed between them and the groups were found to be matching (P≥0.05). The independent t-test was also non-dominant limbs by group. According to the results, the highest reach was achieved in both groups in the medial, lower-side and upper-side directions and these values were slightly higher in the non-dominant compared to the dominant limbs.
The paired t-test was used to compare participants' dominant and non-dominant arms and the results showed no significant differences between the dominant and non-dominant arms in either group (P≥0.05);
however, the independent t-test showed a significant difference between the two groups in the YBT-UQ results (P≤0.05).
The results are presented in Tables 3 and 4.
Science of Gymnastics Journal 284 Science of Gymnastics Journal Table 1
Participants' demographic details (mean ± SD).
P Value
The YBT-UQ results for upper limb length in percentage (mean ± SD).
Rounded-shoulder group
A comparison of the balance scores obtained for the dominant and non-dominant arms using the paired t-test (mean ± SD).
Science of Gymnastics Journal 285 Science of Gymnastics Journal Table 4
Comparison of the balance scores obtained for the healthy and rounded-shoulder groups using the independent t-test (mean ± SD.
P Value assess and compare the functional stability of the upper limbs between a healthy and a rounded-shoulder group of gymnasts using the YBT-UQ. The results showed that the highest reach scores obtained were in the medial direction in both groups, followed by the lower-side and the upper-side directions. These results are somewhat consistent with the results of previous studies; for instance, Westrick et al. (2012) reported the highest reach scores in the YBT-UQ in the medial, lower-side and upper-side directions (Westrick et al., 2012). In another study on the functional stability of the upper limbs in healthy volleyball players and those with anterior instability of the shoulder joint, Zandi et al.
(2015) also reported the highest reach score in the medial direction in both groups, followed by the lower-side and upper-side directions (Zandi et al., 2016).
Gorman et al. (2012) and Amasay et al.
(2016) obtained similar findings (Amasay et al., 2016; Gorman et al., 2012). These findings can potentially be attributed to the positioning of the free hand in relation to the directions of reach when performing the test, since getting the highest reach score in the medial direction seems
obvious, considering the position of the free hand in relation to the three directions and also given the lower-side and upper-side directions being in front of the free hand (Zandi et al., 2016). When reaching in the lower-side direction, the participants are somewhat able to boost their reach scores by rotating their body; in the upper-side direction, however, where the free compared to other directions (Zandi et al., 2016).
The findings also revealed higher reach scores for the non-dominant limbs compared to the dominant limbs in all three directions; however, Table 3 shows no significant differences between the reach scores obtained for the dominant and non-dominant limbs in the healthy and rounded-shoulder groups (P≥0.05). These results are consistent with the majority of previous findings on the functional stability of the dominant and non-dominant upper limbs (Butler et al., 2014; Gorman et al., 2012; Lite et al., 2013; Westrick et al., 2012). For instance, Westrick et al. (2012)
Science of Gymnastics Journal 286 Science of Gymnastics Journal reported no significant differences between
participants' YBT-UQ scores in the dominant and non-dominant limbs (Westrick et al., 2012). Gorman et al.
(2012) also obtained similar results(Gorman et al., 2012). Nonetheless, some studies have reported disparate findings; for instance, Wilson et al. (2013) compared YBT-UQ results in water polo players and reported a significant difference between the reach scores obtained in the upper-side direction for the dominant and non-dominant limbs and attributed this difference to the stabilizing function of the non-dominant limbs in water polo players and argued that, since the supporting hand has a very similar role in the upper-side direction to the role of the non-dominant hand in stabilizing the body when passing and shooting in water polo, participants' are significantly more competent when performing the YBT-UQ using their non-dominant hand compared to the dominant hand in the upper-side direction, hence the significant difference between the reach scores of the limbs in the noted direction(Wilson et al., 2013).
This stabilizing role is not observed in gymnastics movements and the dominant and non-dominant hands appear to be equally involved in gymnastics movements, which could be one of the reasons for the lack of a significant difference between the scores obtained for the different limbs in the present study. In another study, Zandi et al. (2015) also found a significant difference in the YBT-UQ scores between the dominant and non-dominant limbs (Zandi et al., 2016). The difference in the results between this and the present study can be explained by noting the difference in participants' characteristics; in Zandi’s study, the participants had anterior instability of the shoulder joint in one of their limbs and it is only normal that this asymmetry in the characteristics of the limbs should cause a difference in the functional stability of the shoulders and thereby a difference between the reach scores obtained in the YBT-UQ
(Zandi et al., 2016). In the present study, however, participants’ dominant and non-dominant limbs were symmetrical. An inefficient sensory-motor system and the proprioception of the pectoral girdle are also likely to occur as a result of shoulder
(Zandi et al., 2016). In the present study, however, participants’ dominant and non-dominant limbs were symmetrical. An inefficient sensory-motor system and the proprioception of the pectoral girdle are also likely to occur as a result of shoulder